Projecting an image of a real object

ABSTRACT

In some examples, a projection capture system comprises a controller, a camera operatively connected to the controller for capturing images of an object on a work surface of a workspace, a projector operatively connected to the controller, and a mirror above the projector to reflect light from the projector onto the work surface. The camera is located higher than the projector, and the controller is to control the camera to capture an image of a real object on the work surface, and control the projector to project the image of the real object onto the work surface.

CROSS REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. application Ser. No. 14/130,943, filed Jan. 6, 2014, which is a national stage application under 35 U.S.C. §371 of of PCT/US2011/058896, filed 2 Nov. 2011, which claims priority from PCT/US2011/053947, filed 29 Sep. 2011; PCT/US2011/046253, filed 2 Aug. 2011; and PCT/US2011/045983, filed 29 Jul. 2011, which are all hereby incorporated by reference in their entirety.

BACKGROUND

Various types of mixed reality systems have been developed to produce new environments where real and virtual objects co-exist and interact in real time. Virtual whiteboard and other types of remote collaboration systems have also been developed to enable remote users to share and manipulate information simultaneously at multiple locations.

DRAWINGS

FIGS. 1A and 1B are perspective, exterior views illustrating one example of a new projection capture system. In FIG. 1A, the image of a two dimensional object (a hardcopy photograph) has been captured and displayed. In FIG. 1B, the image of a three dimensional object (a cube) has been captured and displayed.

FIG. 2 is a perspective, interior view illustrating one example a new projection capture system.

FIG. 3 is a block diagram of the projection capture system shown in FIG. 2.

FIG. 4 is block diagram illustrating one example of a user input device in the system shown in FIGS. 2 and 3.

FIGS. 5 and 6 are side and front elevation views, respectively, illustrating the positioning of the camera and the projector in the projection capture system shown in FIGS. 2 and 3.

FIGS. 7-11 are a progression of side elevation views showing various positions for the projector and the camera in a projection capture system, illustrating some of the problems associated with moving the glare spot out of the camera capture area.

FIGS. 12 and 13 illustrate one example of the camera in the projection capture system shown in FIGS. 2 and 3.

FIG. 14 illustrates one example of the projector in the projection capture system shown in FIGS. 2 and 3.

FIGS. 15 and 16 illustrate examples of the user input device in the projection capture system shown in FIGS. 2 and 3.

FIGS. 17-19 are perspective views illustrating one example of a new portable projection capture device.

FIGS. 20-22 illustrate three example scenarios for using a projection capture system with other devices.

FIG. 23 is a block diagram illustrating one example of a new projection capture device that includes object recognition and audio/video teleconferencing capabilities.

FIG. 24 is a block diagram illustrating one example architecture for implementing a projection capture device such as the one shown in FIG. 23 in a collaborative environment.

FIG. 25 is a block diagram illustrating one example of a controller for implementing a layering technique in which real and virtual objects are treated as visually interchangeable logical layers.

FIG. 26 shows a projection capture system in which real checkers are positioned on a virtual checkerboard projected on to the work surface.

FIG. 27 illustrates one example of Z axis layering for the real and virtual objects in the system of FIG. 26.

FIG. 28 is a flow chart illustrating one example method for implementing a layering technique in which real and virtual objects are treated as visually interchangeable logical layers.

The same part numbers designate the same or similar parts throughout the figures.

DESCRIPTION

The examples shown in the figures and described below illustrate but do not limit the invention, which is defined in the Claims following this Description.

A new projection capture system has been developed to improve the interactive user experience working with real objects and projected objects on a physical work surface and to improve virtual collaboration among multiple remote users. The new system may be implemented, for example, in one or more stand-along portable devices deployed on an ordinary work surface. A digital camera, projector and control programming are housed together in a desktop unit that enables a projection augmented virtual reality in which real and projected/virtual objects can be manipulated and shared simultaneously among multiple remote users. Such portable devices can be deployed almost anywhere at any time for interactive collaboration across a comparatively inexpensive platform suitable not only for larger, enterprise business environments but also for small businesses and even personal consumers.

As used in this document, a “real” object means an object that is not displayed, projected or otherwise rendered as an image; and a “virtual” object means an object that is displayed, projected or otherwise rendered as an image.

Examples of a new projection capture system and portable projection capture devices will be described first with reference to FIGS. 1-19. Examples of the implementation of the new projection capture system and devices in a collaborative environment will then be described with reference to FIGS. 20-28.

Projection Capture System and Devices

FIGS. 1A and 1B are perspective, exterior views illustrating one example of a new projection capture system 10 and an interactive workspace 12 associated with system 10. FIG. 2 is a perspective view illustrating one example of a projection capture system 10 with exterior housing 13 removed. FIG. 3 is a block diagram of system 10 shown in FIG. 2. Referring to FIGS. 1A, 1B, 2, and 3, projection capture system 10 includes a digital camera 14, a projector 16, and a controller 18. Camera 14 and projector 16 are operatively connected to controller 18 for camera 14 capturing an image of an object 20 in workspace 12 and for projector 16 projecting the object image 22 into workspace 12 and, in some examples, for camera 14 capturing an image of the projected object image 22. The lower part of housing 13 includes a transparent window 21 over projector 16 (and infrared camera 30).

In the example shown in FIG. 1A, a two dimensional object 20 (a hardcopy photograph) placed onto a work surface 24 in workspace 12 has been photographed by camera 14 (FIG. 2), object 20 removed to the side of workspace 12, and object image 22 projected onto a work surface 24 where it can be photographed by camera 14 (FIG. 2) and/or otherwise manipulated by a user and re-projected into workspace 12. In the example shown in FIG. 1B, a three dimensional object 20 (a cube) placed onto work surface 24 has been photographed by camera 14 (FIG. 2), object 20 removed to the side of workspace 12, and object image 22 projected into workspace 12 where it can be photographed by camera 12 and/or otherwise manipulated by a user and re-projected into workspace 12.

In one example implementation for system 10, controller 18 is programmed and projector 16 is configured to project object image 22 into the same position in workspace 24 as the position of object 20 when its image was captured by camera 14. Thus, a one-to-one scale digital duplicate 22 of an object 20 can be projected over the original allowing a digital duplicate in its place to be manipulated, moved, and otherwise altered as desired by a local user or by multiple remote users collaborating in the same projected workspace 12. The projected image can also be shifted away from the original, allowing a user to work with the original and the duplicate together in the same workspace 12.

System 10 also includes a user input device 26 that allows the user to interact with system 10. A user may interact with object 20 and/or object image 22 in workspace 12 through input device 26, object image 22 transmitted to other workspaces 12 on remote systems 10 (not shown) for collaborative user interaction, and, if desired, object image 22 maybe photographed by camera 14 and re-projected into local and/or remote workspaces 12 for further user interaction. In FIG. 1A, work surface 24 is part of the desktop or other underlying support structure 23. In FIG. 1B, work surface 24 is on a portable mat 25 that may include touch sensitive areas. In FIG. 1A, for example, a user control panel 27 is projected on to work surface 24 while in FIG. 1B control panel 27 may be embedded in a touch sensitive area of mat 25. Similarly, an A4, letter or other standard size document placement area 29 may be projected onto work surface 24 in FIG. 1A or printed on a mat 25 in FIG. 1B. Of course, other configurations for work surface 24 are possible. For example, it may be desirable in some applications for system 10 to use an otherwise blank mat 25 to control the color, texture, or other characteristics of work surface 24, and thus control panel 27 and document placement area 29 may be projected on to the blank mat 25 in FIG. 1B just as they are projected on to the desktop 23 in FIG. 1A.

In the example shown in FIG. 4, user input device 26 includes an infrared digital stylus 28 and an infrared camera 30 for detecting stylus 28 in workspace 12. Although any suitable user input device may be used, a digital stylus has the advantage of allowing input in three dimensions, including along work surface 24, without a sensing pad or other special surface. Thus, system 10 can be used on a greater variety of work surfaces 24. Also, the usually horizontal orientation of work surface 24 makes it useful for many common tasks. The ability to use traditional writing instruments on work surface 24 is advantageous over vertical or mobile computing interfaces. Projecting an interactive display on to a working desktop mixes computing tasks with the standard objects that may exist on a real desktop, thus physical objects can coexist with projected objects. As such, the comfort of using real writing instruments as well as their digital counterparts (like stylus 28) is an effective use model. A three-dimensional pad-free digital stylus enables annotation on top of or next to physical objects without having a sensing pad get in the way of using traditional instruments on work surface 24.

In one example implementation for system 10, projector 16 serves as the light source for camera 14. Camera capture area 32 (FIG. 12) and projector display area 34 (FIG. 14) overlap on work surface 24. Thus, a substantial operating efficiency can be gained using projector 16 both for projecting images and for camera lighting. The light path from projector 16 through workspace 12 to work surface 24 should be positioned with respect to camera 14 to enable user display interaction with minimal shadow occlusion while avoiding specular glare off work surface 24 and objects in workspace 12 that would otherwise blind camera 14. The system configuration described below avoids the glare induced artifacts that would result from a conventional camera lighting geometry while still maintaining a sufficiently steep incident angle for the projector light path desired for proper illumination and projection of two and three dimensional objects in workspace 12.

Ideally, projector 16 would be mounted directly over workspace 12 at an infinite height above work surface 24 to insure parallel light rays. This configuration, of course, is not realistic. Even if projector 16 was moved down to a realistic height above work surface 24 (but still pointing straight down), the projector's light would be reflected off glossy and semi-glossy surfaces and objects straight back into camera 14, creating a blinding specular glare. Thus, the glare spot must be moved out of camera capture area 32. (Specular glare refers to glare from specular reflection in which the angle of incidence of the incident light ray and the angle of reflection of the reflected light ray are equal and the incident, reflected, and normal directions are coplanar.)

To achieve a commercially reasonable solution to this problem of specular glare, camera 14 and projector 16 are shifted away from the center of capture and display areas 32, 34 and projector 16 is positioned low, near base 36, as shown in FIGS. 5 and 6, and a fold mirror 38 is introduced into the projector's light path to simulate a projector position high above work surface 24. The simulated position of projector 16 and the corresponding light path above mirror 38 are shown in phantom lines in FIGS. 5 and 6. However, before describing the configuration shown in FIGS. 5 and 6 in more detail, it is helpful to consider the problems associated with other possible configurations for moving the glare spot out of camera capture area 32.

In FIG. 7, camera 14 is positioned at the center of capture area 32 with an overhead projector 16 slightly off center so that camera 14 does not block the projector light path. In the configuration of FIG. 7, the specular glare spot 39 (at the intersection of incident light ray 41 and reflected light ray 43) falls within capture area 32 and, thus, will blind camera 14 to some objects and images in capture area 32. In addition, for the configuration shown in FIG. 7, where camera 14 and projector 16 are both positioned high above the base, system 10 would be top heavy and, thus, not desirable for a commercial product implementation. If projector 16 is positioned to the side the distance needed to move glare spot 39 out of camera capture area 32, as shown in FIG. 8, the corresponding projector lens offset required would not be feasible. Also, any product implementation for the configuration of system 10 shown in FIG. 8 would be undesirably broad and top heavy.

Moving camera 14 off center over capture area 32 brings projector 16 in to make the system less broad, as shown in FIG. 9, but the projector lens offset is still too great and the product still top heavy. In the configuration shown in FIG. 10, projector 16 is raised to a height so that it may be brought in close enough for an acceptable lens offset but, of course, the product is now too tall and top heavy. The most desirable solution is a “folded” light path for projector 16, shown in FIGS. 5 and 11, in which the “high and tight” configuration of FIG. 10 is simulated using fold mirror 38. In FIGS. 5 and 11, projector 16 and the upper light path are folded over the reflecting surface of mirror 38 to project the same light path on to work surface 24 as in the configuration of FIG. 10. This folding effect is best seen in FIG. 5 where fold angles Θ1=θ2 and φ1=φ2.

As shown in FIGS. 5 and 6, camera 14 is placed in front of the mirror 38 over workspace 12 so that it does not block the projector's light path. Camera 14 is positioned off center in the Y direction (FIG. 5) as part of the overall geometry to keep glare spot 39 out of capture area 32 with an acceptable offset for both camera 14 and projector 16. Projector 16 is focused on mirror 38 so that light from projector 16 is reflected off mirror 38 into workspace 12. By moving projector 16 down low and introducing a fold mirror 38 into the projector light path, glare spot 39 is kept out of capture area 32 with an acceptable projector offset and system 10 is sufficiently narrow, short and stable (not top heavy) to support a commercially attractive product implementation.

Thus, and referring again to FIGS. 1A, 1B, and 2, the components of system 10 may be housed together as a single device 40. Referring also to FIG. 3, to help implement system 10 as an integrated standalone device 40, controller 18 may include a processor 42, a memory 44, and an input/output 46 housed together in device 40. Input/out 46 allows device 40 to receive information from and send information to an external device, as described below with reference to FIGS. 20-22. While input/output 46 is shown in FIG. 3 as being part of controller 18, some or all of input/output 46 could be separate from controller 18.

For the configuration of controller 18 shown in FIG. 3, the system programming to control and coordinate the functions of camera 14 and projector 16 may reside substantially on controller memory 44 for execution by processor 42, thus enabling a standalone device 40 and reducing the need for special programming of camera 14 and projector 16. Programming for controller 18 may be implemented in any suitable form of processor executable medium including one or more software modules, hardware modules, special-purpose hardware (e.g., application specific hardware, application specific integrated circuits (ASICs), embedded controllers, hardwired circuitry, etc.), or some combination of these. Also, while other configurations are possible, for example where controller 18 is formed in whole or in part using a computer or server remote from camera 14 and projector 16, a compact standalone appliance such as device 40 shown in FIGS. 1A, 1B and 2 offers the user full functionality in an integrated, compact mobile device 40.

Referring now to FIG. 12, camera 14 is positioned in front of mirror 38 above workspace 12 at a location offset from the center of capture area 32. As noted above, this offset position for camera 14 helps avoid specular glare when photographing objects in workspace 12 without blocking the light path of projector 16. While camera 14 represents generally any suitable digital camera for selectively capturing still and video images in workspace 12, it is expected that a high resolution digital camera will be used in most applications for system 10. A “high resolution” digital camera as used in this document means a camera having a sensor array of at least 12 megapixels. Lower resolution cameras may be acceptable for some basic scan and copy functions, but resolutions below 12 megapixels currently are not adequate to generate a digital image sufficiently detailed for a full range of manipulative and collaborative functions. Small size, high quality digital cameras with high resolution sensors are now quite common and commercially available from a variety of camera makers. A high resolution sensor paired with the high performance digital signal processing (DSP) chips available in many digital cameras affords sufficiently fast image processing times, for example a click-to-preview time of less than a second, to deliver acceptable performance for most system 10 applications.

Referring now also to FIG. 13, in the example shown, camera sensor 50 is oriented in a plane parallel to the plane of work surface 24 and light is focused on sensor 50 through a shift lens 52. This configuration for sensor 50 and lens 52 may be used to correct keystone distortion optically, without digital keystone correction in the object image. The field of view of camera 14 defines a three dimensional capture space 51 in work space 12 within which camera 14 can effectively capture images. Capture space 51 is bounded in the X and Y dimensions by camera capture area 32 on work surface 24. Lens 52 may be optimized for a fixed distance, fixed focus, and fixed zoom corresponding to capture space 51.

Referring to FIG. 14, projector 16 is positioned near base 36 outside projector display area 34 and focused on mirror 38 so that light from projector 16 is reflected off mirror 38 into workspace 12. Projector 16 and mirror 38 define a three dimensional display space 53 in workspace 12 within which projector 16 can effectively display images. Projector display space 53 overlaps camera capture space 51 (FIG. 12) and is bounded in the X and Y dimensions by display area 34 on work surface 24. While projector 16 represents generally any suitable light projector, the compact size and power efficiency of an LED or laser based DLP (digital light processing) projector will be desirable for most applications of system 10. Projector 16 may also employ a shift lens to allow for complete optical keystone correction in the projected image. As noted above, the use of mirror 38 increases the length of the projector's effective light path, mimicking an overhead placement of projector 16, while still allowing a commercially reasonable height for an integrated, standalone device 40.

One example of suitable characteristics for system 10 as a standalone device 40 are set out in Table 1. (Dimension references in Table 1 are to FIGS. 5 and 6.)

TABLE 1 CAMERA PROJECTOR Sensor Mpixel 12 Mp Sensor aspect 1.333 ratio X/Y Pixel size .00175 mm CX Object full size X 427 mm PX Illum Full-field X 310 mm CY Object full size Y 320 mm PY Illum Full-field Y 310 mm CH Camera height 450 mm PH Projector height 670 mm CS Camera shift in Y 150 mm PS Projector shift in Y 330 mm Magnification⁻¹ 66 Sensor pixels X 4016 Lens offset 216% Sensor pixels Y 3016 Lens shift 108% Sensor size X 7.028 mm Max Y-fan angle 35.76 deg Sensor size Y 5.278 mm Min Y-fan angle 14.84 deg Image size X 6.470 mm Half-field X 203.5 mm Image size Y 4.848 mm Half-field Y 482.5 mm Half-field X 213.5 mm Throw ratio 1.65 Half-field Y 280 mm Max throw angle 38.01 deg Full-field angle 76.08 deg CC Camera clearance 51.6 mm distance Sampling 220 ppi GC Glare spot clearance 44.4 mm resolution distance Capture length X 464.85 mm Capture length Y 348.35 mm

Since projector 16 acts as the light source for camera 12 for still and video capture, the projector light must be bright enough to swamp out any ambient light that might cause defects from specular glare. It has been determined that a projector light 200 lumens or greater will be sufficiently bright to swamp out ambient light for the typical desktop application for system 10 and device 40. For video capture and real-time video collaboration, projector 16 shines white light into workspace 12 to illuminate object(s) 20. For an LED projector 16, the time sequencing of the red, green, and blue LED's that make up the white light are synchronized with the video frame rate of camera 14. The refresh rate of projector 16 and each LED sub-frame refresh period should be an integral number of the camera's exposure time for each captured frame to avoid “rainbow banding” and other unwanted effects in the video image. Also, the camera's video frame rate should be synchronized with the frequency of any ambient fluorescent lighting that typically flickers at twice the AC line frequency (e.g., 120 Hz for a 60 Hz AC power line). An ambient light sensor can be used to sense the ambient light frequency and adjust the video frame rate for camera 14 accordingly. For still image capture, the projector's red, green, and blue LED's can be turned on simultaneously for the camera flash to increase light brightness in workspace 12, helping swamp out ambient light and allowing faster shutter speeds and/or smaller apertures to reduce noise in the image.

The example configuration for system 10 integrated into a standalone device 40 shown in the figures and described above achieves a desirable balance among product size, performance, usability, and cost. The folded light path for projector 16 reduces the height of device 40 while maintaining an effective placement of the projector high above workspace 12 to prevent specular glare in the capture area of camera 12. The projector's light path shines on a horizontal work surface 24 at a steep angle enabling 3D object image capture. This combination of a longer light path and steep angle minimizes the light fall off across the capture area to maximize the light uniformity for camera flash. In addition, the folded light path enables the placement of projector 16 near base 36 for product stability.

Suitable input devices and techniques for use in system 10 include, for example, finger touch, touch gestures, stylus, in-air gestures, voice recognition, head tracking and eye tracking. A touch pad can be used to enable a multi-touch interface for navigating a graphical user interface or performing intuitive gesture actions like push, flick, swipe, scroll, pinch-to-zoom, and two-finger-rotate. Depth cameras using structured light, time-of-flight, disturbed light pattern, or stereoscopic vision might also be used to enable in-air gesturing or limited touch and touch gesture detection without a touch pad. A touch-free digital stylus is particularly well suited as a user input 26 for system 10. Thus, in the example shown in the figures, user input 26 includes an infrared digital stylus 28 and an infrared camera 30 for detecting stylus 28 in workspace 12. As noted above, a touch-free digital stylus has the advantage of allowing input in three dimensions, including along work surface 24, without a sensing pad or other special surface.

Referring now to FIGS. 4 and 15, input device 26 includes infrared stylus 28, infrared camera 30 and a stylus charging dock 54. Stylus 28 includes an infrared light 56, a touch sensitive nib switch 58 to turn on and off light 56 automatically based on touch, and a manual on/off switch 60 to manually turn on and off light 56. (Nib switch 58 and manual switch 60 are shown in the block diagram of FIG. 4.) Light 56 may be positioned, for example, in the tip of stylus 28 as shown in FIG. 15 to help maintain a clear line-of-sight between camera 30 and light 56. Light 56 may also emit visible light to help the user determine if the light is on or off.

Nib switch 58 may be touch sensitive to about 2 gr of force, for example, to simulate a traditional writing instrument. When the stylus's nib touches work surface 24 or another object, nib switch 58 detects the contact and turns on light 56. Light 56 turning on is detected by camera 30 which signals a touch contact event (similar to a mouse button click or a finger touch on a touch pad). Camera 30 continues to signal contact, tracking any movement of stylus 28, as long as light 56 stays on. The user can slide stylus 28 around on any surface like a pen to trace the surface or to activate control functions. When the stylus nib is no longer in contact with an object, light 56 is switched off and camera 30 signals no contact. Manual light switch 60 may be used to signal a non-touching event. For example, when working in a three dimensional workspace 12 the user may wish to modify, alter, or otherwise manipulate a projected image above work surface 24 by manually signaling a “virtual” contact event.

Infrared camera 30 and mirror 38 define a three dimensional infrared capture space 61 in workspace 12 within which infrared camera 30 can effectively detect light from stylus 28. Capture space 61 is bounded in the X and Y dimensions by an infrared camera capture area 62 on work surface 24. In the example shown, as best seen by comparing FIGS. 14 and 15, infrared camera capture space 61 is coextensive with projector display space 53. Thus, infrared camera 30 may capture stylus activation anywhere in display space 53.

In one example implementation shown in FIG. 16, camera 30 is integrated into the projection light path such that the projector field-of-view and the infrared camera field-of-view are coincident to help make sure stylus 28 and thus the tracking signal from infrared camera 30 is properly aligned with the projector display anywhere in workspace 12. Referring to FIG. 16, visible light 64 generated by red, green and blue LEDs 66, 68, and 70 in projector 16 passes through various optics 72 (including a shift lens 74) out to mirror 38 (FIG. 14). Infrared light 75 from stylus 28 in workspace 12 reflected off mirror 38 toward projector 16 is directed to infrared camera sensor 76 by an infrared beam splitter 78 through a shift lens 80. (Similar to the example configuration for camera 14 described above, infrared light sensor 76 for camera 30 may be oriented in a plane parallel to the plane of work surface 24 and light focused on sensor 76 through shift lens 80 for full optical keystone correction.)

It may be desirable for some commercial implementations to house projector 16 and infrared camera 30 together in a single housing 82 as shown in FIG. 16. The geometrical configuration for infrared camera 30 shown in FIG. 16 helps insure that the stylus tracking signal is aligned with the display no matter what height stylus 28 is above work surface 24. If the projector field-of-view and the infrared camera field-of-view are not coincident, it may be difficult to calibrate the stylus tracking at more than one height above work surface 24, creating the risk of a parallax shift between the desired stylus input position and the resultant displayed position.

Although it is expected that workspace 12 usually will include a physical work surface 24 for supporting an object 20, work space 12 could also be implemented as a wholly projected work space without a physical work surface. In addition, workspace 12 may be implemented as a three dimensional workspace for working with two and three dimensional objects or as a two dimensional workspace for working with only two dimensional objects. While the configuration of workspace 12 usually will be determined largely by the hardware and programming elements of system 10, the configuration of workspace 12 can also be affected by the characteristics of a physical work surface 24. Thus, in some examples for system 10 and device 40 it may be appropriate to consider that workspace 12 is part of system 10 in the sense that the virtual workspace accompanies system 10 to be manifested in a physical workspace when device 36 is operational, and in other examples it may be appropriate to consider that workspace 12 is not part of system 10.

FIGS. 17-19 are perspective views illustrating another example of a portable projection capture device 40 and an interactive workspace 12 associated with device 40. Referring to FIGS. 17-19, portable device 40 includes a digital camera 14 for capturing still and video images of an object 20 in capture area 32 (and in capture space 51) and a projector 16 for illuminating an object in capture area 32 (and capture space 51) and for projecting images onto display area 34 (and into a display space 53). A two dimensional object 20 (a hardcopy photograph) placed in capture area 32 has been photographed by camera 14 (FIGS. 17 and 18), object 20 removed from capture area 32, and an object image 22 projected onto display area 34 (FIG. 19) where it can be photographed by camera 14 and/or otherwise manipulated by a user.

In this example, device 40 also includes an electronic display 84 for selectively displaying a live feed from camera 14, an image previously captured by camera 14, or the representation of an image as it is manipulated by the user through a graphical user interface (GUI) 86 projected into display space 53. (GUI 86 is projected onto display area 32 in the example shown in FIGS. 17-19.) Camera 14, projector 16, and display 84 are operatively connected together through a controller 18 and housed together in housing 13 as a single portable device 40. Projector 16 is positioned below camera 14 high in housing 13 to project light directly into display space 53 and on to display area 34. Projector display space 53 and display area 34 overlap camera capture space 51 and capture area 32 so that projector 16 can serve as the light source for camera 14 capturing images of real objects 20 in space 51 and on area 32 and so that camera 14 can capture images of images 20 projected into space 51 and on area 32.

Controller 18 is programmed to generate and projector 16 projects a GUI 86 that includes, for example, device control “buttons” such as Capture button 88 in FIGS. 17 and 18 and Undo, Fix, and OK buttons 90, 92, and 94, respectively, in FIG. 19. Although device 40 in FIGS. 17-19 might also include a more complex GUI and corresponding control programming in controller 18, as well as other user input device(s), the device configuration of FIGS. 17-19 illustrates basic digital copying and image manipulation functions more suitable for a less expensive consumer desktop product market.

The examples of system 10 and device 40 shown in the figures, with one camera 14 and one projector 16, do not preclude the use of two or more cameras 14 and/or two or more projectors 16. Indeed, it may be desirable in some applications for a system 10 and device 40 to include more than one camera, more than one projector or more than one of other system components.

Projection Capture in a Collaborative Environment

FIGS. 20-22 illustrate three example scenarios for using a projection capture device 40 with other devices. In the use scenario of FIG. 20, projection capture device 40 is linked to a computer workstation 88 and a mobile device 90. In the use scenario of FIG. 21, multiple projection capture devices 40 are linked together through a server 92. In the use scenario of FIG. 22, projection capture devices 40, computer workstation 88, and mobile device 90 are linked together through a server 92. Each link 94 in FIGS. 20-22, represents generally one or more of a cable, wireless, fiber optic, or remote connection via a telecommunication link, an infrared link, a radio frequency link, or any other connector or system that enables electronic communication between the linked devices. While individual links 94 are shown, multiple devices might utilize the same link. Also, other use scenarios are possible. For example, multiple projection capture devices 40 could be linked together directly, without a server 92.

In each of the scenarios illustrated in FIGS. 20-22, individual users can create, manipulate, transfer, and store virtual objects with devices 40, 88, 90 and multiple users can collaborate among devices 40, 88, 90 with a mixture of real and virtual objects. Virtual objects include, for example, digital content rendered as projected images at projection capture devices 40 as well as digital content rendered on a display as slides, documents, digital photos and the like at other devices 88 and 90. As noted above with reference to FIGS. 1A, 1B, 2, and 3, each projection capture device 40 may be configured to project an object image 22 into the same position in workspace 24 as the position of object 20 when its image was captured by camera 14. Thus, a one-to-one scale digital duplicate 22 of an object 20 can be projected over the original allowing a digital duplicate in its place to be manipulated, moved, and otherwise altered as desired by remote users collaborating in workspaces 12 projected at devices 40 or displayed at devices 88, 90. Any suitable alteration technique may be used including, for example, touch and gesture recognitions such as “pinch to zoom” or input from IR stylus 28 for a projection device 40 and/or altering a digital file for a computing device 88, 90. The projected image can also be shifted away from the original, allowing a user to work with the original and the duplicate together in the same workspace 12.

FIG. 23 is a block diagram illustrating one example of a projection capture device 40 that includes audio and a video teleconferencing feature 96. Referring to FIG. 23, conferencing feature 96 includes a front facing camera 98, a microphone 100, and a speaker 102. The addition of conferencing feature 96 allows device 40 to function as a full featured collaboration tool. Projection capture device 40 in FIG. 23 also includes an object recognition device 104 for distinguishing between real and virtual objects in the workspace. In the example shown, object recognition device 104 includes an infrared camera 106 and an infrared light 108. Where workspace camera 14 will see real objects and projected images (virtual objects), infrared camera 106 will see only the real objects. Thus, the video stream (or still image data) from cameras 14 and 106 may be used to distinguish real objects from virtual objects in the workspace, for example through programming residing on controller 18.

An LED, laser or other suitable infrared light 108 may be used with camera 106 to illuminate the workspace to improve object recognition. Also, while it may be possible to use the same infrared camera for both object recognition (camera 106) and for sensing an IR stylus (camera 30 in FIGS. 4, 15, and 16), it is expected that the camera frame rate for object recognition usually will not need to be as high as the frame rate for sensing stylus position but may require higher resolution. Consequently, it may be desirable for some implementations to use separate infrared cameras for object recognition and stylus sensing. IR camera 106 is just one example of a suitable objection recognition device 104. Other implementations are possible. A depth camera, for example, could be used in device 40 instead of an IR camera to distinguish between real and virtual objects in the workspace.

FIG. 24 illustrates one example architecture for the programming and signal processing to implement a projection capture device 40 from FIG. 23 in a collaborative environment. In this example, real and virtual objects are managed separately. Real objects captured with a workspace camera 14 are managed through motion video while virtual objects are managed through still image graphics elements such as bitmap images, vector graphics objects, and text. For a stand-alone projection capture device 40, the blocks shown in FIG. 24 are implemented in controller 18. Referring to FIG. 24, the video streams from workspace camera 14 and front facing camera 98 go to an outgoing video manager 110 where they are output to linked devices at block 112. Still images from workspace camera are routed to an object manager 114. Object manager 114 is the system component that stores and manipulates digital content, including compositing image objects for projector display at block 116 and compositing image objects for output to linked devices at block 118. The audio signals from conferencing microphone 100 go to an outgoing audio manager 120 where they are output to linked devices at block 112. Input from linked devices at block 122 is routed to the appropriate manager—still images are routed to object manager 114, video is routed to an incoming video manager 124 for output to object compositing 116 and projector 16, and audio is routed to an incoming audio manager 126 for output to speaker 102.

One example for managing the interaction between real and virtual objects will now be described with reference to FIGS. 25-28. In this example, real and virtual objects are treated as visually interchangeable logical layers that allow a projection capture device to interpret and control its workspace and, in a collaborative environment, to help each user interact effectively with local and remote objects. FIG. 25 is a block diagram illustrating one example for implementing this layering technique through a programming module 128 residing on projection capture device controller 18. Layering module 128 associates a real object with one visual layer (or set of layers) and associates a virtual object with another visual layer (or set of layers). As noted above with reference to FIG. 24, real objects captured with a workspace camera 14 are managed through digital motion video while virtual objects are managed through digital still image graphic elements. Object manager 114 stores and manipulates digital content, including visual layering implemented in layering module 128. In one example, each video and still image digital element is associated with a position in an XYZ coordinate system. Layering module 128 uses the XYZ position information to characterize the relative position of each element with layers in each plane of the coordinate system—the XY, XZ, and YZ planes. The visual position of each element may then be altered by manipulated the corresponding layer(s). For example, where the XY layer for one object (or element in an object) may initially appear to be above the XY layer for another object, controller 18 may alter this visual positioning by moving one or both layers in the Z direction.

Reference will now be made to FIGS. 26 and 27 to help illustrate the layering technique. FIG. 26 shows a projection capture device 40 and workspace 12 in which real checkers 130 are positioned on a virtual checkerboard 132 projected on to work surface 24. Workspace 12 also includes virtual checkers 134 projected on to checkerboard 132, for example using digital content from one or more linked devices 40, 88, 90 in FIG. 22. Solid lines indicate real objects in FIG. 26 and dashed lines indicate virtual objects. FIG. 27 illustrates Z axis layering for the objects in FIG. 26. The Z axis position of double (kinged) checkers is represented by logical layer 136 on top of layer 138. Layer 138 represents the position of single checkers on top of layer 140. Layer 140 represents the position of virtual checkerboard 132 on top of layer 142 which represents the position of work surface 24. Once the position of an object or an element in an object is associated with a logical layer, layering module 128 (FIG. 25) maintains state information about the visual order of the layers. As the visual relationships are changed, for example when a checker in FIG. 26 is moved, the layers are reordered according to new position data associated with one or more of the digital elements.

In general, and referring to the flow chart of FIG. 28 along with the block diagrams of FIGS. 23 and 25, controller 18 identifies the presence and location of a real object in workspace 12 at block 202, for example using workspace camera 14 and object recognition device 104. At block 204, layering module 128 associates the real object with a first logical layer (or a first set of logical layers for three dimensional spatial positioning). At block 206, a virtual object (an object image) is projected into workspace 12 at a location corresponding to a second logical layer. Then, in response to a change in the position of one of the objects or in response to some other user input, layering module 128 alters the visual adjacency of the logical layers to reflect the change/input at block 208. For example, the first layer might initially be visually adjacent to work surface 24 and the second layer visually adjacent to the first layer. In response to a change/input, the order of the layers is reversed so that the second layer becomes visually adjacent to work surface 24 and the first layer becomes visually adjacent the second layer.

The use of a projection capture system 10 (through a portable device 40 for example) in a collaborative environment such as that shown in FIGS. 20-22, enables each collaborator to see and interact with both local and remote objects. A live video feed among linked devices shares user input in real time through a variety of different input devices and techniques. While collaborator interaction may be more comprehensive when every participant is using a projection capture device 40 (or system 10), an effective collaborative environment is still available using different types of devices. Interesting cooperative work is possible where one participant uses a projection capture system 10 and the other participants use devices running system 10 client programming. In such “mixed” environments, instead of interacting with a system 10 workspace, a participant would use a mouse, keyboard or touchpad to interact through the client programming. Instead of a projection display, a client programming on a collaborative device 88 or 90 may use a window display in the computer workspace. And, instead of an overhead camera, the client application could use screen shots to capture object images.

As noted at the beginning of this Description, the examples shown in the figures and described above illustrate but do not limit the invention. Other examples, embodiments and implementations are possible. Therefore, the foregoing description should not be construed to limit the scope of the invention, which is defined in the following claims. 

What is claimed is:
 1. A projection capture system, comprising: a controller; a camera operatively connected to the controller for capturing images of an object on a work surface of a workspace; a projector operatively connected to the controller; and a mirror above the projector to reflect light from the projector onto the work surface, wherein the camera is located higher than the projector, the controller to: control the camera to capture an image of a real object on the work surface, and control the projector to project the image of the real object onto the work surface.
 2. The projection capture system of claim 1, wherein the controller is to control the projector to project the image of the real object onto the work surface as a one-to-one scale digital duplicate of the real object.
 3. The projection capture system of claim 2, wherein the controller is to control the projector to project the image of the real object onto the work surface at the same position occupied by the real object when the image of the real object was captured by the camera.
 4. The projection capture system of claim 1, wherein the controller, the camera, the projector, and the mirror are housed together as a single portable unit.
 5. The projection capture system of claim 1, wherein the projector is a light source for the camera during capture of the images by the camera.
 6. The projection capture system of claim 5, wherein the controller is to control the projector to produce a time sequencing of different color light that is synchronized with a video frame rate of the camera during capture of video images by the camera.
 7. The projection capture system of claim 1, wherein the mirror is to simulate a projector position above the work surface.
 8. The projection capture system of claim 7, wherein the simulating of the projector position causes a folding effect where the projector is folded over a reflecting surface of the mirror to project a same light path onto work surface as if the projector were provided above the mirror.
 9. The projection capture system of claim 1, wherein the controller is to: control the camera and the projector to capture an image of the image of the real object as the image of the real object is being altered in the workspace including the work surface, and project the altered image of the real object into the workspace.
 10. A non-transitory processor readable storage medium storing instructions that upon execution: cause a camera to capture an image of a real object on a work surface in a first workspace of a projection capture device including the camera and a projector; and cause the projector to project the image of the real object onto the work surface, wherein the causing of the projecting of the image of the real object onto the work surface comprises causing the projector to project the image of the real object to a mirror located above the projector, the mirror to reflect the image of the real object into the first workspace, and the camera located higher than the projector.
 11. The non-transitory processor readable medium of claim 10, wherein the projector is a light source for the camera during capture of the image of the real object by the camera, and wherein the instructions when executed cause a time sequencing of different color light produced by the projector to be synchronized with a video frame rate of the camera during the capture of the image of the real object by the camera.
 12. The non-transitory processor readable medium of claim 10, the image of the real object is projected onto the work surface at the same position occupied by the real object when the image of the real object was captured.
 13. The non-transitory processor readable medium of claim 10, wherein the instructions upon execution cause simultaneous projecting of-the image of the real object into a plurality of workspaces including the first workspace.
 14. The non-transitory processor readable medium of claim 10, wherein the instructions upon execution cause a controller to: receive information relating to altering of the image of the real object in the first workspace; and cause each of multiple projectors to project the altered image of the real object simultaneously into each respective workspace of a plurality of workspaces.
 15. The non-transitory processor readable medium of claim 10, wherein the mirror is to simulate a projector position above the work surface.
 16. The non-transitory processor readable medium of claim 15, wherein the simulating of the projector position causes a folding effect where the projector is folded over a reflecting surface of the mirror to project a same light path onto work surface as if the projector were provided above the mirror.
 17. A method comprising: capturing, by a camera, a digital image of a real object on a work surface in a first workspace; and projecting, by a projector, the image of the real object to a mirror located above the projector, the mirror reflecting the image of the real object onto the work surface, wherein the camera is located higher than the projector.
 18. The method of claim 17, further comprising: causing, by a controller, simultaneous projecting of the image of the real object into multiple workspaces including the first workspace; receiving, by the controller, an altered object image as altered in one of the multiple workspaces; and causing, by the controller, simultaneous projecting of the altered object image into the multiple workspaces including the first workspace.
 19. The method of claim 18, wherein projecting the image of the real object into the multiple workspaces comprises projecting the image of the real object as a one-to-one scale digital duplicate of the real object.
 20. The method of claim 17, wherein the mirror is to simulate a projector position above the work surface. 